Dengue fever is caused by an arbovirus, transmitted to humans by the bite of an aedes mosquito. Four different serotypes of dengue virus have been identified. Infection with one serotype provides life long immunity to that specific serotype, but only partial short term immunity to other 3 serotypes. Dengue is mainly an urban disease present in tropical and sub tropical regions.
Primary or first infection may be asymptomatic or present as mild dengue fever, subsequent infections are dangerous. The incubation or latent period is of 4-10 days, thereafter illness occurs in three phases, which are described as follows –
Febrile Phase: Marked by high fever 39 – 40 0C accompanied by generalized body aches, rash, and bleeding manifestations. It usually lasts for 2-7 days.
Critical Phase: Marked by decrease in temperature, it usually occurs between 3rd to 7th
WHO has classified dengue according to severity of symptoms
Dengue with warning signs:– It includes fever with two of the following symptoms :-
Nausea / vomiting
Rash resembling measles
Decreased white cell counts
Dengue with warning signs: Marked by presence of at least one of these signs
Pain in stomach
Decrease in platelets
Severe Dengue: Marked by following
Fluid leaks presenting as accumulation of fluid around the liver and in lungs
Weak and rapid pulse
Factors that put you at greater risk of developing dengue fever or a more severe form of the disease include:
Living or traveling in tropical areas.Being in tropical and subtropical areas increases your risk of exposure to the virus that causes dengue fever. Especially high-risk areas are Southeast Asia, the western Pacific islands, Latin America and the Caribbean.
Prior infection with a dengue fever virus.Previous infection with a dengue fever virus increases your risk of having severe symptoms if you’re infected again.
There is no specific medication for treatment of a dengue infection. People who think they have dengue should use analgesics (pain relievers) with acetaminophen and avoid those containing ibuprofen, Naproxen, aspirin or aspirin containing drugs. They should also rest, drink plenty of fluids to prevent dehydration, avoid mosquito bites while febrile and consult a physician.
As with dengue, there is no specific medication for DHF. If a clinical diagnosis is made early, a health care provider can effectively treat DHF using fluid replacement therapy. Adequately management of DHF generally requires hospitalization.